Lidar Filtering of High Frequency Waves “Understanding characteristics of the near space environment”

The objective of this study is to gain a better understanding of gravity waves and associated characteristics in the near space environment by developing new lidar filtering techniques. Gravity waves, which are also known as buoyancy waves, can be observed from the troposphere to the thermosphere of our atmosphere. These waves can be generated in the lower atmosphere through convection, wind shear, topography, and other sources at lower altitudes [Fritts and Alexander, 2003]. As gravity waves propagate into higher altitudes they transport energy and momentum which can significantly influence the near space environment.
By using resonance fluorescence atmospheric Light Detection and Ranging (lidar) we are able to obtain high resolution measurements of winds, temperatures, and sodium densities associated with the sodium layer located in the near space environment ~80-100 km. To obtain these data the lidar system sends a laser pulse into the atmosphere and then measures the scattering that returns to the system in the form of photon counts. The returning signal can tell us much about our atmosphere, such as the temperature, wind, and density perturbations associated with gravity waves at specific altitudes. This project will use data from the sodium lidar previously at the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) and continuing data from the sodium lidar now at Poker Flat in Chatanika, AK.